Many parents think that dilated pupils can harm their children’s eyesight, so they are concerned and even refuse to give their children dilated pupils. Many opticians do not perform dilated eye examinations, but why do doctors in hospitals recommend them? In particular, dilated pupils are required before excimer laser surgery.
Dilated pupils require pupil dilation, which is only a superficial phenomenon. The essence of dilated pupils is to completely relax the ciliary muscle and loosen the adjustment to get the true refractive state of the eye. The eye is like an “auto-zoom” camera that can see both near and far through the contraction and relaxation of the ciliary muscle and the elasticity of the lens.
If the pupil is not dilated during optometry, the adjustment of the ciliary muscle can cause the lens to become more convex and the refractive power to increase, which will not remove the adjustment of myopia, the so-called pseudomyopia. For this reason, adolescent optometry requires routine pupil dilatation to relax the ciliary muscle and completely paralyze it to avoid the effects of adjustment spasms and to ensure the authenticity and accuracy of the optometry.
The importance of dilated pupils has been gradually recognized, and it is well known that dilated pupils are required for adolescents under the age of 18. However, dilated pupils should also be used for adjusted myopia and hyperopia over the age of 18 in order to relax the adjustment and obtain an accurate refraction. Many parents think that dilated pupils can harm their child’s vision, so they have many concerns and even refuse to dilate their child’s pupils. In fact, dilated pupils are a temporary effect of the medication and only have a temporal effect on children.
After the pupil is dilated, the child will experience temporary photophobia and difficulty seeing close to the eye, which will return after a period of time.
The method of pupil dilatation is relatively simple and involves the loss of ciliary muscle regulation. Children under the age of 14 should have their pupils dilated slowly with atropine, while children over the age of 14 can have their pupils dilated quickly with atropine. Precautions for atropine pupil dilatation: 1% atropine ophthalmic ointment, twice daily for 7 days, with an optometric examination at the hospital on the 8th day.
The rapid pupil dilatation can be performed after 5 doses of the medicine and the pupil is checked for dilatation, and the pupil can be restored 5-6 hours after the test. However, not all children can be examined with dilated pupils. For example, cases such as shallow anterior chamber and high intraocular pressure should be examined in detail before optometry, so dilated pupils need to be examined in a regular hospital.
Adverse effects of atropine
(1) Atropine dilates the pupil and it is normal for patients to experience photophobia and difficulty seeing near.
(2) Avoid bright light stimulation during pupil dilatation, and wear a sun hat or sunglasses for outdoor activities.
(3) Due to blurred vision during pupil dilatation, children should be watched carefully to avoid bruising.
(4) The purpose of dilating the pupil is to relax the regulation of the ciliary muscle, so try not to use the eyes at close range during this period.
(5) In a very small number of children, if symptoms such as flushing, thirst, fever, headache, nausea and vomiting, hallucinations, or excitement appear after pupil dilatation, consider this to be an adverse reaction to atropine and stop the drug immediately or consult an ophthalmologist.
(6) It takes about 3 weeks after atropine is discontinued for the pupil to return to normal, but the time for pupil recovery may vary depending on individual differences.
Cases in which dilated pupils are not appropriate
(1) Patients with suspected glaucoma who are examined and found to have a shallow anterior chamber and intraocular pressure that is high or at the high limit of normal. A detailed medical history should be taken to clarify this before optometry is performed.
(2) Glaucoma patients are contraindicated to apply dilated pupil optometry, otherwise it will lead to an increase in intraocular pressure.
(3) People over 40 years of age generally no longer have dilated pupils for optometry because of reduced ciliary muscle regulation.
(4) In severe lens and vitreous clouding and corneal white spots, dilated pupillometry is meaningless because of the difficulty in detecting shadow.
(5) In severe posterior or anterior pupillary adhesions, the pupil is not normally dilated even after the application of pupil-dilating medication, so there is no need to dilate the pupil for optometry.